The present invention relates to a pointing device for moving a pointer (cursor) on a display screen used for a portable information terminal such as a cellular phone, and a portable information terminal using the pointing device.
Conventionally, a portable information terminal such as a portable type personal computer and cellular phone has an operation panel provided with a display screen on which a pointer for pointing to a desired position of an image is displayed and a pointing device for moving this pointer to a desired position.
As such a conventional pointing device, a track ball that moves a pointer by detecting the rotation of a ball and a dial type pointer that moves a pointer by detecting the rotation of a disk are known. Furthermore, as portable information terminals are being increasingly implemented with multi-functions and large-sized display screen, and in order to make it possible to arbitrarily and smoothly select more selection items with a pointer, a cross pointer having independent feed switches for upward/downward, rightward/leftward movements of a pointer and a stick pointer used for a game machine in particular that moves a pointer by tilting a stick or disk back and forth, right and left are also known. Furthermore, as used for a personal computer, etc., to continuously move a pointer on an image such as a map displayed on a display screen, a pointing device called a “track pad” is also known which consists of a flat table shaped sensor plate with a certain area and when a finger is moved continuously on this sensor plate, the continuously changing position of the finger is detected and the pointer is moved continuously according to this detection result.
On the other hand, since a portable information terminal must meet the need for portability, there is a demand for a smaller, lighter or thinner terminal. For the track ball or dial type pointing device above, meeting this demand is difficult because this pointing device includes a physical movable section such as a ball or disk, which puts a limit to reduction of the size.
With the pointing device such as the cross pointer and stick pointer above, the pointer basically moves one step by one operation, that is, the pointer moves by one item displayed on the display screen at a time, and therefore selecting an item at a considerable distance on the display screen requires more operations, which takes time and trouble.
Moreover, the track pad described above moves the pointer by touching the sensor plate with the finger and therefore the sensor plate must have an area sufficiently greater than the area of the finger that touches this and is not suited to miniaturization.